250 watts: why so much power?

Personally, i would consider an amp rated at 250 wpc @ 8 ohms to be "good sized" and not "big". Like all things in life, points of view will vary based on one's perspective : )

As to why someone might need that much power, I had temporarily hooked up an amp that is rated for 200 wpc @ 8 ohms / 350 wpc @ 4 ohms to my HT mains today. These speakers are a nominal 4 ohm load and are about 85 - 86 db's in terms of sensitivity. As such, they are less than average sensitivity and what most would consider a low impedance load. Into this type of load, the amp should be delivering 350-375 wpc rms and probably at least 4-500 wpc on peaks.

Upon playing a classical piece by Rimsky-Korsakov entitled "Allegro Molto" at what i consider to be "good volume", the amp was noticeably going into compression and lacked bass sustain during the "high impact" parts of the selection. Instruments were getting smeared together due to amplifier saturation. Switching back over to the amp that i usually use to drive these, which is rated at 1200 wpc and clips at 1400+ rms, i had no problems. The bass had much greater impact and sustain and instruments did not get as "bunched up" sounding. This was because the amp was still "coasting" and not being pushed hard. As such, it was easily able to keep up with the demand for power and the result was cleaner operation with less smearing, compression and distortion.

And just in case you were wondering, it was wonderfully dynamic, loud and still crystal clear : ) Sean
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A few years ago I switched speakers from generally efficient ones to a quite inefficient pair. The amps driving my old speakers did so beautifully with 100 watts of class A power per channel. However,they were totally inadequate to drive the new speakers--it was as if there was a lid on the speakers, which had nothing of the openness they had had at the dealer's showroom. I had to buy a pair of 350 watt per channel amps. Now, those same speakers have been reconfigured by the manufacturer, and are much more efficient. The 350 watt amps just coast, the volume control on the preamp is much lower, and I am sure my old amps would work just fine again.

Mgottlieb, can you expand on what you consider to be efficient and inefficient? Where does the line cross?

How loud do you "high powered" guys listen to music? How big are your rooms?

Headroom.

Matchstikman: I just checked things out playing the same recording set to the same volume level. The mains are spread appr 12.5' apart ( center to center ) and toe'd in a bit. While this is not ideal for two channel reproduction with these specific speakers, this is my HT system and i have things dialed in for optimum use with a large ( two eight's, dome mid, dome tweeter ) center channel. As such, i need to spread the mains out just a bit more than normal, which also results in a very wide soundstage with excellent center fill due to the center channel taking over on movies. Even with this wide of placement and the center turned off for standard "stereophonic reproduction", imaging and soundstage is quite acceptable. Since I was using the system in 2 channel mode via the mains only when i made the above comments, that is how i measured it.

Ambient noise level in the room is below 50 dB's, which is as low as i can measure. At my seated listening position and the meter just behind where my head would normally be, I am hitting peaks of 108 - 110 db's sitting 10' away from the speakers. The average level of the recording is easily 20 - 30 dB's ( and sometimes much lower ) than this. As such, there is a great deal of dynamic contrast as the tempo and volume changes during this specific performance. This is a very exciting Classical performance, even for a "rocker" like me : )

For those that are "playing along", i'm using a stock Realistic 33-2050 analogue SPL meter. It was set to the "C" weighting and fast response. I also have a highly modified version of the same meter that is much more linear in response ( and would have shown higher peaks ), but i used the stock RS meter so that others with such units might be able to do a more direct comparison. Sean
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